Israel is going to attack Iran and the United States is going to get dragged back into another Middle Eastern War. I can grantee the US will help Israel as or foreign policy demands it for some reason, plus we wont let Israel take on Iran alone because they would lose. Israel has an active military force of 3,000,000 men and women who are legally obligated to serve, Iran has 23,000,000 able body men that are legally obligated to serve. If Israel attacks Iran, Iran will attempt to deal with them, however if the United States becomes involved which it will, Iran will feel backed into a corner, and seeing how Iran is a country of religious zealots, they will have no problem 'sharing' their nuclear weapons (if they indeed have them) with Israel and the United States. If Iran indeed does launch a nuclear weapon its possible that Israel will respond with their own nukes(at this point it is unknown if Israel has nukes, but no one said they could not) resulting in a small nuclear war. This is the worse possible outcome, their are far better options but this outcome is very possible...
Report: IDF find M-16 rifle hidden in Palestinian's car in West Bank (Haaretz)